<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      * {
        padding: 0;
        margin: 0;
      }
      html,
      body {
        width: 100%;
        height: 100%;
      }
      /* 第一种 */
      .container {
        display: flex;
        height: 100%;
        flex-direction: column;
      }
      .context {
        flex: 1;
        border: 1px solid red;
      }

      .foot {
        width: 100%;
        height: 60px;
        border: 1px solid blue;
      }

      /* 第二种 */
      .container {
        position: relative;
        height: 100%;
        width: 100%;
      }

      .context {
        width: 100%;
        /* height: 100%; */
        /* height: calc(100vh - 50px); */
        height: calc(100vh - 60px);
        border: 1px solid red;
      }

      .foot {
        position: fixed;
        width: 100%;
        height: 60px;
        left: 0;
        right: 0;
        bottom: 0;
        border: 1px solid blue;
      }
    </style>
  </head>
  <body>
    <div class="container">
      <div class="context">内容区</div>
      <div class="foot">底部导航</div>
    </div>

    <script>
      //   var str: number = 1;
      //   var str: string = 1;
      //   var str: null = 1;
      //   undefined、array 、object 、 boolean  function
      const array = [];
      Array.isArray();
      Object.prototype.toString.call(array) === "[object Array]";
    </script>
  </body>
</html>
